This invention relates to a motorcycle provided with a receiving chamber having a relatively large capacity capable of receiving a large article, such as a helmet.
Motorcycles having a receiving chamber for a helmet, or the like, provided under the seat thereof are known. In these prior art arrangements, the engine stands substantially upright with the transmission case extending rearwardly therefrom and a substantially horizontal portion of the body frame being formed above the rear wheel. An upwardly open box-like receiving chamber is provided on the horizontal body frame portion, and a seat is mounted on the opening of the chamber so that the chamber may be opened and closed by pivoting the seat. Examples of such prior art are disclosed, for example, in Japanese Patent Publication No. 9478/1987 and Japanese Utility Model Laid-Open No. 26089/1984.
In the case of the above described construction, it is necessary to maintain adequate spacing between the approximately horizontal portion of the body frame and the engine. The height of the seat from the ground, also has a fixed limitation. Therefore, it is impossible to set the depth of the receiving chamber so deep as to obtain a large capacity. For this reason, the size of an article received into the receiving chamber naturally involves a fixed restriction. For example, it is difficult to form the receiving chamber with a capacity capable of receiving a relatively large article, such as a full-face type helmet.
Another problem encountered in such conventional prior art motorcycles is that, in the event that an attempt is made to increase the diameter of the rear wheel, steps taken to avoid interference between the receiving chamber and the rear wheel including moving the rear wheel shaft rearwardly, or raising the entire receiving chamber upwardly, or, alternatively, raising only the bottom of the receiving chamber. When the rear wheel shaft is moved rearwardly, the wheel base becomes undesirably extended. On the other hand, when the entire receiving chamber is raised upwardly, the seat, present on the upper surface of the chamber, is raised and, therefore, the height of the seat from the ground increases. When, on the other hand, only the bottom of the chamber is raised upwardly, the volume of the receiving chamber is reduced, possibly to the extent of failing to receive a helmet therein.
The present invention seeks to ameliorate the above-described problems.